The present disclosure relates to a turntable for a spindle motor and a spindle motor having the same.
Generally, a spindle motor is widely used in an optical disk drive (ODD) and a hard disk for rotating a disk at a high speed.
The spindle motor for rotating a disk at a high speed includes a rotation shaft, a bearing rotatably supporting the rotation shaft in a rotational shaft hole, a bearing housing accommodating the bearing, a stator secured at the bearing housing, a rotor coupled to the rotation shaft to rotate in association with the stator and a turntable coupled to the rotation shaft to accommodate a disk.
Recently, an automatic balancing system (ABS) with balls arranged in a round groove is widely employed in which a round groove is formed at a bottom surface of a turntable to reduce vibration of the rotation shaft when a disk is rotated at a high speed that is caused by eccentricity generated in the course of manufacturing of the turntable. The balls arranged in the round groove are positioned precisely opposite to an eccentric portion to reduce the vibration generated by the eccentricity.
However, there is a disadvantage in the balls of the ABS in that the balls roll along the turntable inside the round groove to move to a portion opposite to the eccentric portion, where the balls collide each other if the frictional forces of the balls and the turntable are too small, and if the frictional forces of the balls and the turntable are too great, it takes a long time for the balls to move to an opposite portion of the eccentric portion or the balls cannot precisely move to the opposite portion of the eccentric portion.